1. Technical Field
The present disclosure relates to machining methods, and particularly, to a hole machining method for drilling holes in circuit boards.
2. Description of Related Art
In machining a circuit board, some holes are usually defined in the circuit board. One method is to drill a number of intersectant small holes to form a hole.
Referring to FIG. 1, a schematic view of a hole machining method to drill a drill area 20 for a machined hole 30 on a circuit board is shown. In order to more easily understand the related-art hole machining method, the intersectant small holes are not shown as being intersectant in FIG. 1. The related-art hole machining method includes the following steps. In steps S1 and S2, drilling two holes 1 and 2 at opposite ends of the drilling area 20 respectively, setting the two holes 1 and 2 as a start point and an end point of the hole 30. In step S3, drilling a hole 3 in the drilling area 20, at a middle point between the start point and the end point of the drilling area 20. In steps S4 and S5, setting the two holes 1 and 3 as a first new start point and a first new end point and setting the two holes 3 and 2 as a second new start point and a second new end point, and then drilling a hole 4 in the drilling area 20 at a middle point between the first new start point and the first new end point, and drilling a hole 5 in the drilling area 20 at a middle point between the second new start point and the second new end point. In steps S6 to S17, drilling other holes according to the above steps, until all holes are drilled in the drilling area 20, therefore, all the holes, such as seventeen holes 1-17 combine to form the hole 30.
In related art, the following is the usual method to determine the number of holes to be drilled to form a needed hole. The number of holes to be drilled is equal to 2n +1, where “n” is a minimum natural number which can satisfy that 2n+1 is greater than or equal to a needed number of holes for forming the hole 30. For example, if a needed number of holes for forming the hole 30 is ten, then n=4, and the number of actual holes is then seventeen. Because when n=3, then 2n+1=9<10, which does not satisfy the requirement, while when n=4, then 2n+1=17>10, which satisfies the requirement. However, when n=4, extra seven holes (17−10=7) must be drilled, which reduces machining efficiency.